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Wetland

For other uses, see Wetland (disambiguation).
Upland vs. wetland vs. lacustrine zones
Freshwater swamp forest in Bangladesh
Peat bogs are freshwater wetlands that develop in areas with standing water and low soil fertility.
Mount Polley wetlands in British Columbia, Canada
Wetlands come in different sizes, types, and locations. Clockwise from top left: Upland vs. wetland vs. lacustrine zones; Freshwater swamp forest in Bangladesh; A freshwater cattail (Typha) marsh that develops with standing water and high soil fertility; Peat bogs are freshwater wetlands that develop in areas with standing water and low soil fertility.

A wetland is a distinct ecosystem that is flooded or saturated by water, either permanently for years or decades or seasonally for a shorter periods. Flooding results in oxygen-free anoxic processes prevailing, especially in the soils.[1] The primary factor that distinguishes wetlands from terrestrial land forms or water bodies is the characteristic vegetation of aquatic plants, adapted to the unique anoxic hydric soils.[2] Wetlands are considered among the most biologically diverse of all ecosystems, serving as home to a wide range of plant and animal species. Methods for assessing wetland functions, wetland ecological health, and general wetland condition have been developed for many regions of the world. These methods have contributed to wetland conservation partly by raising public awareness of the functions some wetlands provide.[3] Constructed wetlands are designed and built to treat municipal and industrial wastewater as well as to divert stormwater runoff. Constructed wetlands may also play a role in water-sensitive urban design.

Wetlands occur naturally on every continent.[4] The water in wetlands is either freshwater, brackish, or saltwater.[2] The main wetland types are classified based on the dominant plants and/or the source of the water. For example, marshes are wetlands dominated by emergent vegetation such as reeds, cattails and sedges; swamps are ones dominated by woody vegetation such as trees and shrubs (although reed swamps in Europe are dominated by reeds, not trees).

Besides being prominent and abundant modern environments and ecosystems, wetlands were also very common throughout Earth history and many sedimentary rock units have been interpreted as representing the geological record of ancient freshwater[5] or coastal wetlands.[6]

Examples of wetlands classified by their sources of water include tidal wetlands (oceanic tides), estuaries (mixed tidal and river waters), floodplains (excess water from overflowed rivers or lakes), springs, seeps and fens (groundwater discharge out onto the surface), and bogs and vernal ponds (rainfall or meltwater).[1][7] Some wetlands have multiple types of plants and are fed by multiple sources of water, making them difficult to classify. The world's largest wetlands include the Amazon River basin, the West Siberian Plain,[8] the Pantanal in South America,[9] and the Sundarbans in the Ganges-Brahmaputra delta.[10]

Wetlands contribute a number of functions that benefit people. These are called ecosystem services and include water purification, groundwater replenishment, stabilization of shorelines and storm protection, water storage and flood control, processing of carbon (carbon fixation, decomposition and sequestration), other nutrients and pollutants, and support of plants and animals.[11] Wetlands are reservoirs of biodiversity and provide wetland products. According to the UN Millennium Ecosystem Assessment, wetlands are more affected by environmental degradation than any other ecosystem on Earth.[12] Wetlands can be important sources and sinks of carbon, depending on the specific wetland, and thus will play an important role in climate change and need to be considered in attempts to mitigate climate change. However, some wetlands are a significant source of methane emissions and some are also emitters of nitrous oxide.[13][14]

  1. ^ a b Keddy, P.A. (2010). Wetland ecology: principles and conservation (2nd ed.). New York: Cambridge University Press. ISBN 978-0521519403. Archived from the original on 2023-03-17. Retrieved 2020-06-03.
  2. ^ a b "Official page of the Ramsar Convention". Retrieved 2011-09-25.
  3. ^ Dorney, J.; Savage, R.; Adamus, P.; Tiner, R., eds. (2018). Wetland and Stream Rapid Assessments: Development, Validation, and Application. London; San Diego, CA: Academic Press. ISBN 978-0-12-805091-0. OCLC 1017607532.
  4. ^ Davidson, N.C. (2014). "How much wetland has the world lost? Long-term and recent trends in global wetland area". Marine and Freshwater Research. 65 (10): 934–941. doi:10.1071/MF14173. S2CID 85617334.
  5. ^ Wright, V. P.; Platt, N. H. (1995-10-01). "Seasonal wetland carbonate sequences and dynamic catenas: a re-appraisal of palustrine limestones". Sedimentary Geology. 99 (2): 65–71. Bibcode:1995SedG...99...65W. doi:10.1016/0037-0738(95)00080-R. ISSN 0037-0738.
  6. ^ Suarez-Gonzalez, P.; Quijada, I. E.; Benito, M. I.; Mas, R. (2015-01-27). "Sedimentology of Ancient Coastal Wetlands: Insights From A Cretaceous Multifaceted Depositional System". Journal of Sedimentary Research. 85 (2): 95–117. Bibcode:2015JSedR..85...95S. doi:10.2110/jsr.2015.07. ISSN 1527-1404.
  7. ^ "US EPA". 2015. Retrieved 2011-09-25.
  8. ^ Fraser, L.; Keddy, P.A., eds. (2005). The World's Largest Wetlands: Their Ecology and Conservation. Cambridge, UK: Cambridge University Press. ISBN 978-0521834049.
  9. ^ "WWF Pantanal Programme". Retrieved 2011-09-25.
  10. ^ Giri, C.; Pengra, B.; Zhu, Z.; Singh, A.; Tieszen, L.L. (2007). "Monitoring mangrove forest dynamics of the Sundarbans in Bangladesh and India using multi-temporal satellite data from 1973 to 2000". Estuarine, Coastal and Shelf Science. 73 (1–2): 91–100. Bibcode:2007ECSS...73...91G. doi:10.1016/j.ecss.2006.12.019.
  11. ^ "Wetlands". USDA- Natural Resource Conservation Center. 2023.
  12. ^ Davidson, N.C.; D'Cruz, R. & Finlayson, C.M. (2005). Ecosystems and Human Well-being: Wetlands and Water Synthesis: a report of the Millennium Ecosystem Assessment (PDF). Washington, DC: World Resources Institute. ISBN 978-1-56973-597-8.
  13. ^ Bange, H. W. (2006). "Nitrous oxide and methane in European coastal waters". Estuarine, Coastal and Shelf Science. 70 (3): 361–374. Bibcode:2006ECSS...70..361B. doi:10.1016/j.ecss.2006.05.042.
  14. ^ Thompson, A. J.; Giannopoulos, G.; Pretty, J.; Baggs, E. M.; Richardson, D. J. (2012). "Biological sources and sinks of nitrous oxide and strategies to mitigate emissions". Philosophical Transactions of the Royal Society B. 367 (1593): 1157–1168. doi:10.1098/rstb.2011.0415. PMC 3306631. PMID 22451101.